Migration of your contact list to SystemeScale: what you need to know before getting started (advanced tips)

Migrating your contacts to SystemeScale may seem straightforward at first, but to avoid costly errors such as undelivered emails, duplicates, corrupted data, or lost contacts, you should follow a methodical process.

This guide explains the most important points to keep in mind before, during, and after migrating your contact list.

I. Preparation before migration

Before importing your contacts, prepare your list carefully. A poorly prepared list can damage deliverability, create duplicate data, or make future segmentation harder.

1. Clean your list

Inactive or invalid addresses can generate email bounces.

• Soft bounce: A temporary issue, such as when a recipient’s inbox is full.
• Hard bounce: A permanent issue, such as when an email address does not exist.

A high bounce rate directly affects your sender reputation and reduces the deliverability of future emails.

Email providers such as Gmail, Outlook, and Yahoo monitor bounce rates. If your bounce rate becomes too high, your emails may land in spam or be blocked entirely.

2. Identify active contacts

An active contact is generally someone who:

• Opened or clicked your emails recently, for example within the last 30–90 days.
• Has not generated any bounces.
• Has not reported your emails as spam.

Start with your most engaged contacts when warming up your sending on a new platform.

3. Sort your contacts

You can sort your contacts inside your current email tool or CRM before exporting them.

Look for options such as Filter, Segment, or Create view, then filter based on criteria such as:

• Status = Active, if your current tool provides an active/inactive field.
• Email opens > 0 in the last 90 days.
• Link clicks > 0 in the last 90 days.
• Bounce = None.
• Unsubscribed = No.

You can also use an email verification tool, such as ZeroBounce or NeverBounce, to identify invalid addresses.

Consider deleting contacts who have not interacted in a long time, such as 6 to 12 months depending on your sending frequency. Also remove generic or suspicious addresses such as test@test.com or admin@domain.com.

4. Verify your file format

Prepare your file properly before import.

• CSV format: SystemeScale imports contact lists using CSV files.
• Clear column labels: Label each column clearly, such as First Name, Last Name, Email, Tags, Registration Date, and other relevant fields.
• UTF-8 encoding: Use UTF-8 encoding to avoid corrupted characters.
• Duplicate removal: Identify repeated emails before import to avoid multiple entries for the same contact.

II. Segment your contacts

Segmentation means dividing your contact list into groups based on precise criteria such as interests, behavior, location, purchase history, source, or engagement level.

Segmentation improves campaign effectiveness because targeted emails usually generate stronger engagement than generic blasts.

• By interest or category: Product A, Product B, service interest, topic preference.
• By behavior: Active customers, inactive prospects, clicked but did not buy.
• By source: Web form, event, webinar, in-store purchase, partner campaign.

Precise targeting also reduces unsubscribes and spam complaints, which helps protect your domain reputation.

III. Double opt-in and compliance

Double opt-in sends a confirmation email after registration to verify that the contact truly wants to receive your emails.

This helps ensure that contacts are genuinely interested, reduces unsubscribes and spam reports, and supports compliance with GDPR and other anti-spam laws such as CAN-SPAM and CASL.

Contacts confirmed through double opt-in are usually more engaged and less likely to flag your emails as spam. A low complaint rate and high engagement can improve overall deliverability.

IV. Data structure and custom fields

Before importing, understand which fields are required, optional, and useful for future segmentation.

Required vs. optional fields

The email field is required because it is the primary identifier for each contact.

Other fields, such as first name, last name, or phone number, are optional but useful for personalization and better targeting later.

Custom fields

You can use custom fields for information such as birthdays, interest levels, or other business-specific data. During import, map these fields accurately so each value is stored in the correct place.

Tags and segments

You can import contacts with existing tags to preserve segmentation from your previous tool. Tags help group contacts based on behavior, interests, or stage in the customer journey.

V. Migration methods

If you use a migration service, a migration manager can help handle the import of your contact file. If you want to perform the migration yourself, manual CSV import is the most controlled method.

Manual import via CSV

This method is suitable for most contact lists and gives you full control over fields, tags, and mapping.

Advantages:

• You can check and correct data before importing.
• You control tag assignment and custom field mapping.
• You can import in batches for safer review and gradual warming.

Steps to follow:

Supported integrations and migration support

For some accounts and workflows, supported integrations or migration assistance may help reduce manual work during a contact migration.

Regardless of the method used, always verify field mapping, tags, and imported data before sending campaigns to migrated contacts.

Important: Resume email sending gradually

When switching email service providers, you should not immediately send high volumes of email from the new platform, even if you were previously used to high-volume sending.

Gradual sending, also called email warming, helps you:

• Establish sender reputation with ISPs such as Gmail, Outlook, and Yahoo.
• Reduce the risk of being blocked or landing in spam.
• Build a stronger sending reputation for future campaigns.
• Improve deliverability and subscriber engagement over time.

In practice, start by sending emails to a small segment of active contacts, then gradually increase volume over several days or weeks.

VI. Post-migration checks

After importing your contacts, perform checks before sending broadly.

• Test send: Send a test email to a small segment to verify deliverability.
• Import report: Review the summary of successfully imported contacts and any errors.
• Field review: Check that email, name, tags, and custom fields imported correctly.
• Segment review: Confirm that your imported tags and groups match your intended segmentation.

VII. Advanced tips for a secure migration

• Migrate in batches: If you have thousands of contacts, import them in smaller groups to manage errors and warm up by segment.
• Use source tags: Add a tag such as migration_2026 to identify the source of migrated contacts and track their behavior.
• Allow processing time: Avoid sending a massive campaign immediately after importing; allow 24 to 48 hours for the servers to process new contacts.
• Keep a backup: Save a copy of your original list before importing.
• Monitor bounces: After migration, monitor bounced emails and adjust your list to avoid reputation issues.

Common migration errors

Error	Consequence	Solution
Incorrect CSV encoding	Corrupted characters	Use UTF-8 encoding.
Mismapped fields	Data loss or misplaced data	Verify every column before importing.
Compliance issues	Legal and deliverability risk	Confirm that all contacts opted in.
Large batch migration	Spam risk and import errors	Migrate in batches and test first.

VIII. Optimizing contacts after migration

After migration, continue improving your contact management over time.

• Dynamic segmentation: Use tags and behavioral criteria to create automated segments.
• Automations: Set up welcome sequences for migrated contacts to improve engagement.
• Continuous analysis: Track open rates, clicks, and unsubscribes, then adjust your strategy.

Related migration and deliverability guides

Use the related guides below to protect deliverability, import contacts correctly, and migrate without damaging sender reputation.